Answer is C (both stmt is required).
1)total hours for three days is 72 hours. So with 60 hours difference you cant say whether its monday or not.
for ex. if appoint. is at 10 am, then subtracting 60 hours is Sunday 10 pm.
and if appoint. is at 3pm, then subtracting 60 hours is Monday.
So, its not sufficient.
But with second option, we know the appointment time. so we can calculate.
Kudos if it helps.
Kudos if any of my post helps you !!!